Multiple pathways for spinal nerve root decompression from a single access point

ABSTRACT

A method of accessing target tissue adjacent to a spinal nerve of a patient includes the steps of accessing a spine location of the patient by entering the patient through the skin at an access location, inserting a flexible tissue modification device through the access location to the spine location, advancing a distal portion of the first flexible tissue modification device from the spine location to a first exit location, passing through the first exit location and out of the patient, advancing the first or a second flexible tissue modification device through the same access location to the spine location and to a second exit location, and passing through the second exit location and out of the patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/352,978, titled “MULTIPLE PATHWAYS FOR SPINAL NERVE ROOTDECOMPRESSION FROM A SINGLE ACCESS POINT”, filed Jan. 13, 2009, whichclaims priority to U.S. Provisional Application No. 61/106,498, titled“MULTIPLE PATHWAYS FOR SPINAL NERVE ROOT DECOMPRESSION FROM A SINGLEACCESS POINT”, filed Oct. 17, 2008, which is incorporated by referenceherein in its entirety.

U.S. application Ser. No. 12/352,978 is also a Continuation-in-Part toU.S. application Ser. No. 11/251,205, titled “DEVICES AND METHODS FORTISSUE ACCESS”, filed Oct. 15, 2005, now U.S. Pat. No. 7,918,849, and toU.S. application Ser. No. 11/687,548, titled “TISSUE REMOVAL WITH ATLEAST PARTIALLY FLEXIBLE DEVICES”, filed Mar. 16, 2007, now U.S. Pat.No. 8,062,298; each of which is incorporated by reference herein in itsentirety.

In addition, the methods described herein may be applied to many of thedevices and systems described in any of the reference listed below. Inparticular, these references described flexible (or partially flexible)tissue modification device that may be manipulated bi-manually (e.g., byapplying force from both ends of the device). This application may berelated to U.S. application Ser. No. 11/250,332, filed Oct. 15, 2005;U.S. application Ser. No. 11/250,369, filed Oct. 15, 2005; U.S.application Ser. No. 11/251,155, filed Oct. 15, 2005; U.S. applicationSer. No. 11/251,205, filed Oct. 15, 2005; U.S. application Ser. No.11/250,902, filed Oct. 15, 2005; U.S. application Ser. No. 11/251,186,filed Oct. 15, 2005; U.S. application Ser. No. 11/251,165, filed Oct.15, 2005; U.S. application Ser. No. 11/251,204, filed Oct. 15, 2005;U.S. application Ser. No. 11/251,199, filed Oct. 15, 2005; U.S.application Ser. No. 11/952,934, filed Dec. 7, 2007; U.S. applicationSer. No. 11/405,848, filed Apr. 17, 2006; U.S. application Ser. No.11/406,486, filed Apr. 17, 2006; U.S. application Ser. No. 11/405,859,filed Apr. 17, 2006; U.S. application Ser. No. 11/429,377, filed May 4,2006; U.S. application Ser. No. 11/457,416, filed Jul. 13, 2006; U.S.application Ser. No. 11/687,548, filed Mar. 16, 2007; U.S. applicationSer. No. 11/687,558, filed Mar. 16, 2007; U.S. application Ser. No.11/375,265, filed Mar. 13, 2006; U.S. application Ser. No. 11/461,740,filed Aug. 1, 2006; U.S. application Ser. No. 11/535,000, filed Sep. 25,2006; U.S. application Ser. No. 11/468,247, filed Aug. 29, 2006; U.S.application Ser. No. 12/127,535, filed May 27, 2008; U.S. applicationSer. No. 11/468,252, filed Aug. 29, 2006; U.S. application Ser. No.11/843,561, filed Aug. 22, 2007; U.S. application Ser. No. 11/538,345,filed Oct. 3, 2006; U.S. application Ser. No. 11/870,370, filed Oct. 10,2007; U.S. application Ser. No. 12/140,201, filed Jun. 16, 2008; U.S.application Ser. No. 12/170,392, filed Jul. 9, 2008; U.S. applicationSer. No. 12/060,229, filed Mar. 31, 2008; U.S. Provisional Application61/017,512, filed Dec. 28, 2007; U.S. Provisional Application61/020,670, filed Jan. 11, 2008; U.S. Provisional Application61/041,215, filed Mar. 31, 2008; U.S. Provisional Application61/048,448, filed Apr. 28, 2008; U.S. Provisional Application61/053,761, filed May 16, 2008; U.S. Provisional Application 61/077,441,filed Jul. 1, 2008; U.S. Provisional Application 61/080,647, filed Jul.14, 2008; U.S. Provisional Application 61/081,685, filed Jul. 17, 2008;U.S. Provisional Application 61/095,568, filed Sep. 9, 2008; U.S.Provisional Application 61/100,145, filed Sep. 25, 2008; each of whichis incorporated by reference herein in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to methods ofaccessing and modifying tissue, particularly methods of accessing andmodifying tissue with flexible tissue modification devices for treatmentof spinal stenosis.

BACKGROUND

A significant number of surgical procedures involve modifying tissue ina patient's body, such as by removing, cutting, shaving, abrading,shrinking, ablating or otherwise modifying tissue. Minimally invasive(or “less invasive”) surgical procedures often involve modifying tissuethrough one or more small incisions or percutaneous access, and thus maybe more technically challenging procedures. Some of the challenges ofminimally invasive tissue modification procedures include working in asmaller operating field, working with smaller devices, and trying tooperate with reduced or even no direct visualization of the tissue (ortissues) being modified. For example, using arthroscopic surgicaltechniques for repairing joints such as the knee or the shoulder, it maybe quite challenging to modify certain tissues to achieve a desiredresult, due to the required small size of arthroscopic instruments, theconfined surgical space of the joint, lack of direct visualization ofthe surgical space, and the like. It may be particularly challenging insome surgical procedures, for example, to cut or contour bone orligamentous tissue with currently available minimally invasive tools andtechniques. For example, trying to shave a thin slice of bone off acurved bony surface, using a small-diameter tool in a confined spacewith little or no ability to see the surface being cut, as may berequired in some procedures, may be incredibly challenging or evenimpossible using currently available devices.

One area of surgery which would likely benefit from the development ofless invasive techniques is the treatment of spinal stenosis. Spinalstenosis occurs when nerve tissue and/or the blood vessels supplyingnerve tissue in the spine become impinged by one or more structurespressing against them, causing symptoms. The most common form of spinalstenosis occurs in the lower (or lumbar) spine and can cause severepain, numbness and/or loss of function in the lower back and/or one orboth lower limb.

FIG. 1 is a top view of a vertebra with the cauda equina (the bundle ofnerves that extends from the base of the spinal cord) shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina (FIG. 2)on either side of the vertebra.

FIG. 2 illustrates the spine in sagittal section. The spine comprisesmultiple vertebrae each having spinous process, facet joint, andintervertebral foramen. Pedicles form inferior and superior boundariesof the intervertebral foramen and are connected to the spinous processby lamina (FIG. 1). Interspinal ligaments extend between adjacentspinous processes, while ligamentum flavum (FIG. 1) connect adjacentlamina and are separated from dura mater and spinal cord (not shown) byepidural space (FIG. 1). Dura mater encapsulates the spinal cord as itruns down the spinal canal, as well as nerve roots as they exit throughthe lateral recesses and neural foramen. Vertebral bodies andintervertebral discs are disposed anterior of the spinal cord.

Spinal stenosis can occur when the spinal cord, cauda equina and/ornerve root(s) are impinged by one or more tissues in the spine, such asbuckled or thickened ligamentum flavum, hypertrophied facet joint (shownas superior articular processes in FIG. 1), osteophytes (or “bonespurs”) on vertebrae, spondylolisthesis (sliding of one vertebrarelative to an adjacent vertebra), facet joint synovial cysts, and/orcollapse, bulging or herniation of an intervertebral disc. Impingementof neural and/or neurovascular tissue in the spine by one or more ofthese tissues may cause pain, numbness and/or loss of strength ormobility in one or both of a patient's lower limbs and/or of thepatient's back.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% (or more) of adults aged 50 and older and is the mostfrequent reason cited for back surgery in patients aged 60 and older.Patients suffering from spinal stenosis are typically first treated withconservative approaches such as exercise therapy, analgesics,anti-inflammatory medications, and epidural steroid injections. Whenthese conservative treatment options fail and symptoms are severe, as isfrequently the case, surgery may be required to remove impinging tissueand decompress the impinged nerve tissue.

Lumbar spinal stenosis surgery involves first making an incision in theback and stripping muscles and supporting structures away from the spineto expose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Furthermore, it isoften difficult to access an entire impinged nerve root to remove allimpinging tissue along the length of the nerve root. This may require asurgeon to remove additional healthy tissue to create multiple accesslocations. Spinal stenosis surgery is performed under generalanesthesia, and patients are usually admitted to the hospital for fiveto seven days after surgery, with full recovery from surgery requiringbetween six weeks and three months. Many patients need extended therapyat a rehabilitation facility to regain enough mobility to liveindependently.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the affected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. Unfortunately, a surgical spine fusion results in a loss ofability to move the fused section of the back, diminishing the patient'srange of motion and causing stress on the discs and facet joints ofadjacent vertebral segments. Such stress on adjacent vertebrae oftenleads to further dysfunction of the spine, back pain, lower leg weaknessor pain, and/or other symptoms. Furthermore, using current surgicaltechniques, gaining sufficient access to the spine to perform alaminectomy, facetectomy and spinal fusion requires dissecting through awide incision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

Therefore, it would be desirable to have less invasive methods foraccessing and modifying target tissue in a spine to help ameliorate ortreat spinal stenosis, while inhibiting unwanted damage to non-targettissues. Ideally, such techniques and devices would reduce neural and/orneurovascular impingement without removing significant amounts ofvertebral bone, joint, or other spinal support structures, therebyavoiding the need for spinal fusion and, ideally, reducing the long-termmorbidity resulting from currently available surgical treatments.Furthermore, such methods would minimize the need to dissect through awide incision or multiple small incisions on the back that typicallycauses extensive muscle damage. It may also be advantageous to haveminimally invasive or less invasive methods and tissue modificationdevices capable of treating target tissues in parts of the body otherthan the spine.

SUMMARY OF THE DISCLOSURE

Any of the methods and devices described herein may be used as part of atissue decompression (e.g., spinal decompression) method to modifytissue such as soft tissue (e.g., ligamenum flavum, etc.) and hardtissue (e.g., bone). In particular, these methods and devices may beused as part of a spinal decompression technique within a spinalforamen.

Described herein are methods of accessing target tissue adjacent to aspinal nerve of a patient. In some embodiments, the method includes thesteps of accessing a spine location of the patient through the skin atan access location that is anterior to the posterior aspect of theligamentum flavum and posterior to the dura mater of the spinal cord andcauda equina; inserting a first flexible tissue modification devicethrough the access location to the spine location; advancing a distalportion of the first flexible tissue modification device from the spinelocation to a first exit location; passing through the first exitlocation and out of the patient; advancing the first or a secondflexible tissue modification device through the same access location tothe spine location and to a second exit location; and passing throughthe second exit location and out of the patient.

In some embodiments, the method further comprises the steps of removingthe first flexible tissue modification device from the patient and/orremoving the second flexible tissue modification device from thepatient. In some embodiments, the method further comprises the steps ofinserting the first, the second, or a third flexible device through thesame access location to the spine location; and advancing the first, thesecond or the third flexible device from the spine location to a thirdexit location.

In some embodiments, the step of advancing the first or the secondflexible tissue modification device to a first or second exit locationcomprises advancing the first or the second flexible tissue modificationdevice to a first or second intervertebral foramen. In some embodiments,the step of passing through a first or a second exit location comprisesleaving a proximal portion of the first or the second flexible tissuemodification in the first or second intervertebral foramen. In someembodiments, the step of advancing the first or a second flexible tissuemodification device comprises advancing the first flexible tissuemodification device through the same access location to the second exitlocation.

In some embodiments, the step of accessing a spine location of thepatient through an access location comprises accessing a spine locationof the patient through an interlaminar window of the patient. In someembodiments, the step of accessing a spine location of the patientthrough an interlaminar window is achieved without removing a portion ofthe patient's lamina. In some embodiments, the step of accessing a spinelocation of the patient through an access location comprises advancingan access device through the access location to the spine location.

In some embodiments, the step of advancing the access device through theaccess location to the spine location comprises advancing the accessdevice into a midline portion of the back of the patient, lateral to aspinous process, and toward the spine location. In some embodiments, thestep of advancing an access device through the access location to thespine location comprises advancing a needle percutaneously through theaccess location to the spine location. In some embodiments, the step ofadvancing an access device through the access location to the spinelocation comprises advancing the access device into a lateral side ofthe back of the patient, through an intervertebral foramen, and towardthe spine location. In some embodiments, the step of advancing the firstflexible device from the spine location to the first exit locationcomprises advancing at least a portion of a probe through the accessdevice from the spine location toward the first exit location, andadvancing a guidewire through the probe such that the guidewire ispositioned at least partially around a target tissue. In someembodiments, the step of passing through the first or second exitlocation and out of the patient comprises advancing the guidewirethrough the first or second exit location and exiting the patient withthe guidewire.

In some embodiments, the step of advancing the first flexible devicefrom the spine location to a first exit location comprises advancing thefirst flexible device from the spine location, anterior to a superiorarticular process, and through a first intervertebral foramen; andwherein the step of advancing the first or the second flexible devicefrom the spine location to the second exit location comprises advancingthe first or second flexible device from the spine location, anterior toa superior articular process, and through a second intervertebralforamen. In some embodiments, the step of advancing the first flexibledevice from the spine location to a first exit location comprisesadvancing the first flexible device from the spine location, anterior toa superior articular process, and through a first intervertebralforamen; and wherein the step of advancing the first or the secondflexible device from the spine location to the second exit locationcomprises advancing the first or second flexible device from the spinelocation, anterior to a superior articular process, and through a secondintervertebral foramen. In some embodiments, the step of advancing thefirst flexible device from the spine location to the first exit locationcomprises advancing the first flexible device from the spine location,anterior to a superior articular process and cephalad to a pedicle, andthrough a intervertebral foramen; and wherein the step of advancing thefirst or second flexible device from the spine location to the secondexit location comprises advancing the first or second flexible devicefrom the spine location, anterior to a lamina and caudal to the pedicle,and through a second intervertebral foramen.

In some embodiments, the step of advancing the first or second flexibledevice from the spine location to the first or second exit locationcomprises positioning the first or second flexible device at leastpartially around a target tissue, and in some embodiments, the step ofpositioning the first or second flexible device at least partiallyaround the target tissue comprises positioning the first or secondflexible device anterior to a superior articular process and posteriorto neuronal tissue. In some embodiments, the step of positioning thefirst or second flexible device at least partially around the targettissue comprises positioning the flexible device within a portion of aligamentum flavum.

In some embodiments, the method further comprises the step of moving thefirst or second flexible device against the target tissue by pulling thefirst or second flexible device from at least one of the distal orproximal end of the first or second flexible device. In someembodiments, the step of moving the first or second flexible deviceagainst a target tissue by pulling the first or second flexible devicefrom at least one of the distal or proximal end of the device comprisesapplying tension to both the proximal end and the distal end of thefirst or second flexible device to drive the flexible device against thetarget tissue. In some embodiments, the step of applying tension to boththe proximal end and the distal end of the first or second flexibledevice to drive the first or second flexible device against the targettissue comprises applying tension to the distal end of the first orsecond flexible device using the guidewire. In some embodiments,applying tension to the distal end of the first or second flexibledevice using the guidewire comprises applying tension to the distal endof the guidewire external to the patient and a proximal end of theguidewire external to the patient.

In some embodiments, the method further comprises the step of modifyingthe target tissue with the first or second flexible device. In someembodiments, the step of modifying a target tissue with the first orsecond flexible device comprises modifying the target tissue with aflexible radio-frequency device. In some embodiments, the step ofmodifying a target tissue with a first or second flexible devicecomprises modifying the target tissue with a flexible abrasion device.In some embodiments, the step of modifying a target tissue with theflexible device comprises modifying the target tissue with a flexiblerongeur device.

In some embodiments, the method further comprises the step of detectingneuronal tissue near the first or second flexible device. In someembodiments, the step of detecting neuronal tissue near the first orsecond flexible device comprises detecting neuronal tissue with thefirst or second flexible device.

In some embodiments, the method includes the steps of accessing a spinelocation of the patient by entering the patient through an accesslocation, wherein the spine location is anterior to the posterior aspectof the ligamentum flavum and posterior to the dura mater of the spinalcord and cauda equina, and the access location is lateral to the spinousprocess; inserting a first flexible device through the access location,through the interlaminar window, and to the spine location; advancing adistal portion of the first flexible device from the spine location,laterally through a first intervertebral foramen; passing through thefirst intervertebral foramen and out of the patient; inserting the firstor a second flexible device through the same access location, throughthe interlaminar window, and to the spine location; and advancing adistal portion of the first or second flexible device from the spinelocation and laterally through a second intervertebral foramen; andpassing through the second intervertebral foramen and out of thepatient. In some embodiments, the step of inserting the first or secondflexible device through the access location, through the interlaminarwindow, and to the spine location is achieved without removing a portionof the patient's lamina.

In some embodiments, the step of advancing the first flexible devicefrom the spine location and laterally through a first intervertebralforamen comprises advancing the first flexible device anterior to theipsilateral superior articular process. In some embodiments, the step ofadvancing the first flexible device from the spine location andlaterally through a first intervertebral foramen comprises positioningthe first flexible device posterior to and adjacent to a first nerveroot, wherein the first nerve root exits through the firstintervertebral foramen, wherein the first intervertebral foramen isdefined by the same vertebra that define the interlaminar window. Insome embodiments, the step of positioning the first flexible deviceposterior to the first nerve root comprises positioning the firstflexible device posterior to and adjacent to the exiting portion of thefirst nerve root.

In some embodiments, the step of advancing the first or second flexibledevice from the spine location and laterally through a secondintervertebral foramen comprises advancing the first or second flexibledevice anterior to the lamina. In some embodiments, the step ofadvancing the first or second flexible device from the spine locationand laterally through a second intervertebral foramen comprisespositioning the flexible device posterior to and adjacent to a secondnerve root, wherein the second nerve root exits through the secondintervertebral foramen, wherein the second intervertebral foramen iscaudal to the first intervertebral foramen. In some embodiments, thestep of positioning the first or second flexible device posterior to thesecond nerve root comprises positioning the first or second flexibledevice posterior to and adjacent to the traversing portion of the secondnerve root.

In some embodiments, the step of advancing the first flexible devicefrom the spine location and laterally through a first intervertebralforamen comprises advancing the first flexible device anterior to acontralateral superior articular process and through a contralateralintervertebral foramen, wherein the contralateral superior articularprocess and the contralateral intervertebral foramen are contralateralto the access location. In some embodiments, the step of advancing thefirst or second flexible device from the spine location, laterallythrough the second intervertebral foramen comprises advancing theflexible device anterior to the lamina, and through the caudalintervertebral foramen, wherein the lamina and the caudal intervertebralforamen are contralateral to the access location and the caudalintervertebral foramen is caudal to the first intervertebral foramen. Insome embodiments, the step of advancing the first or second flexibledevice from the spine location and laterally through the first or secondintervertebral foramen comprises positioning the first or secondflexible device at least partially around a target tissue. In someembodiments, the step of positioning the first or second flexible deviceat least partially around the target tissue comprises positioning thefirst or second flexible device between within a portion of a ligamentumflavum.

In some embodiments, the method further comprises the steps of modifyingthe target tissue with the first or second flexible device. In someembodiments, the steps of modifying the target tissue with the first orsecond flexible device comprises decompressing a nerve root of thepatient at multiple locations along the nerve root. In some embodiments,decompressing the nerve root of the patient at multiple locations alongthe nerve root comprises decompressing the nerve root at least two of acentral canal, a lateral recess, and through the first or secondintervertebral foramen.

In some alternative embodiments, the method includes the steps ofaccessing a spine location of the patient by entering the patientthrough a first access location, wherein the spine location is anteriorto the posterior aspect of the ligamentum flavum and posterior to thedura mater of the spinal cord and cauda equina; inserting a firstflexible tissue modification device through the first access location tothe spine location; advancing a distal portion of the first flexibletissue modification device from the spine location to an exit location;passing through the exit location and out of the patient; inserting thefirst or a second flexible tissue modification device through a secondaccess location to the spine location; advancing a distal portion of thefirst or a second flexible tissue modification device from the spinelocation to the same exit location; and passing through the same exitlocation and out of the patient. In some embodiments, the step ofadvancing the first or second flexible tissue modification device fromthe spine location to the exit location comprises advancing the first orsecond flexible tissue modification device from the spine location to aninterlaminar window.

In some embodiments, the method further comprises the steps of accessinga spine location of the patient through a third access location;inserting the first, the second or a third flexible device through thethird access location to the spine location; and advancing the first,second or third flexible device from the spine location to the same exitlocation.

The methods and devices described herein may be used as part of aguide-based access and decompression system, including those previouslydescribed in any of the patent applications and provisional patentapplications mentioned in this application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section through the posterior aspect of the lumbarspine;

FIG. 2 is a sagittal section through the lumbar spine;

FIG. 3A is a posterior view of the spine indicating decompression pathsat disk level and along the nerve root.

FIG. 3B is a posterior view of the spine indicating a decompression pathfor adjacent level lateral recess decompression.

FIG. 3C is a posterior view of the spine indicating a decompression pathfor central canal decompression.

FIGS. 4A-4G are cross-sectional views through a patient's spine,illustrating a variation of the method of accessing target tissueadjacent to a spinal nerve of a patient.

FIGS. 5A and 5B are cross-sectional views through a patient's spine,illustrating a variation of the method of accessing target tissueadjacent to a spinal nerve of a patient FIGS. 6A and 6B are a lateralview and a posterior view of three vertebrae of a patient's spine.

FIGS. 7A-7D are cross-sectional views through a patient's spine,illustrating a variation of the method of accessing target tissueadjacent to a spinal nerve of a patient.

FIGS. 8A-8C are cross-sectional views through a patient's spine,illustrating variations of the tissue modification devices.

FIGS. 9A-9E are cross-sectional views through a patient's spine,illustrating a variation of the method of accessing target tissueadjacent to a spinal nerve of a patient.

FIG. 10 is a cross-section view through a patient's spine, illustratinga variation of the spine location.

FIG. 11 is a drawing of a variation of a tissue modification device.

DETAILED DESCRIPTION

Various embodiments of methods for accessing target tissue adjacent to aspinal nerve of a patient as well as tissue modification devices andsystems for use in various embodiments of the methods are providedherein. In general, the methods as described herein are for accessingtarget tissue adjacent to a spinal nerve of a patient. In particular,these methods are for accessing and decompressing a spinal stenosis.

Although much of the following description and accompanying figuresgenerally focuses on surgical procedures in spine, in alternativeembodiments, devices, systems and methods of the present invention maybe used in any of a number of other anatomical locations in a patient'sbody. For example, in some embodiments, the methods and devices may beused in minimally invasive procedures in the shoulder, elbow, wrist,hand, hip, knee, foot, ankle, other joints, or other anatomicallocations in the body. Similarly, although some embodiments may be usedto access and remove or otherwise modify ligamentum flavum and/or bonein a spine to treat spinal stenosis, in alternative embodiments, othertissues may be accessed and modified to treat any of a number of otherconditions. For example, in various embodiments, treated tissues mayinclude but are not limited to ligament, tendon, bone, tumor, cyst,cartilage, scar, osteophyte, inflammatory tissue and the like.Non-target tissues may include neural tissue and/or neurovascular tissuein some embodiments or any of a number of other tissues and/orstructures in other embodiments. In one alternative embodiment, forexample, a flexible tissue modification device may be used to incise atransverse carpal ligament in a wrist while inhibiting damage to themedian nerve, to perform a minimally invasive carpal tunnel releaseprocedure. Thus, various embodiments described herein may be used toaccess and modify any of a number of different tissues, in any of anumber of anatomical locations in the body, to treat any of a number ofdifferent conditions.

Any of the methods and devices described herein may be used to accessand modify tissue, particularly spinal tissue. In particular, thesemethods and devices may be used to access and decompress a region of thespine, such as the region within a spinal foramen. Any of these devicesmay be used as part of a bimanual method (see, for example, theincorporated references). Such bimanual devices may include anattachment site for one or more handles (e.g., proximally) and/or one ormore guidewires. For example, the distal end of the device may beconfigured to releasably secure to a guidewire so that the device may bepulled into position within the body (e.g., within a spinal foramen).

Methods for Accessing Target Tissue

In some embodiments, the method of accessing target tissue adjacent to aspinal nerve of a patient includes the steps of accessing a spinelocation of the patient by entering the patient through the skin at anaccess location; inserting a flexible tissue modification device throughthe access location to the spine location; advancing a distal portion ofthe first flexible tissue modification device from the spine location toa first exit location; passing through the first exit location and outof the patient; advancing the first or a second flexible tissuemodification device through the same access location to the spinelocation and to a second exit location; and passing through the secondexit location and out of the patient. In some embodiments, the spinelocation is anterior to the posterior aspect of the ligamentum flavumand posterior to the dura mater of the spinal cord and cauda equina. Insome embodiments, as shown in FIG. 4A, the spine location 100 is theepidural space. In some embodiments, as shown in FIG. 10, the spinelocation 100′ is within a portion of a ligamentum flavum LF. The methodsare designed for accessing target tissue, and more specifically, foraccessing and decompressing a spinal stenosis. Furthermore, the methodsare designed for decompressing a nerve root of the patient at multiplelocations along the nerve root, all from a single access point. Themultiple locations along the nerve root may include at least two of acentral canal, a lateral recess, and through the first or secondintervertebral foramen of the patient. The methods however, may bealternatively used for any other suitable disease, in any suitableenvironment and for any suitable reason.

FIGS. 6A and 6B illustrate a posterior view and a lateral view,respectively, of a portion of a spine of a patient. The portion of thespine shown includes, labeled from top to bottom, first lumbar vertebra501, second lumbar vertebra 504, and third lumbar vertebra 514. Thefirst lumbar vertebra includes left inferior articular process 502 andright inferior articular process 503. The second lumbar vertebraincludes left pedicle 505, a right pedicle (not shown), left superiorarticular process 506, right superior articular process 507, spinousprocess 508, and lamina of vertebral arch 509. Intervertebral disc 510is disposed between the first lumbar vertebra and the second lumbarvertebra. Interlaminar window 511 is defined by the first lumbarvertebra and the second lumbar vertebra. The third lumbar vertebraincludes third lamina of vertebral arch 515. The first lumbar vertebraand the second lumbar vertebra define two intervertebral foramen: leftintervertebral foramen 512, cephalad to the left pedicle, and a rightintervertebral foramen (not shown), cephalad to the right pedicle. Thesecond lumbar vertebra and the third lumbar vertebra define twointervertebral foramen: caudal left intervertebral foramen 513, caudalto the left pedicle, and a caudal right intervertebral foramen (notshown), caudal to the right pedicle. The third lumbar vertebra and afourth lumbar vertebra (not shown) define two intervertebral foramen:third left intervertebral foramen 516, and a third right intervertebralforamen (not shown).

The step of accessing a spine location of the patient by entering thepatient through the skin at an access location provides access (i.e.creates a channel) from the patient's skin to the spine location suchthat surgical instruments, drugs, or any other suitable device mayaccess the spine location and/or target tissue. Although this step isshown in reference to placement of a device in a spine, in variousalternative embodiments, such a method may be used to place similar oralternative tissue modification devices in other locations in a humanbody, such as between tissues in a joint space, in the abdominal cavity,or in the carpal tunnel of the wrist, between bone and soft tissue inother parts of the body, and the like.

In some variations, the step of accessing a spine location of thepatient through an access location includes the steps of entering thepatient's skin, passing through an interlaminar window of the patient'sspine, passing through at least a portion of the ligamentum flavum, andentering the spine location. The step of entering the patient's skin maybe completed by inserting a needle and/or creating an incision. In somevariations, the incision may be widened through the use of surgicalinstruments, such as retractors for example. In some variations, thestep of passing through the interlaminar window of the patient's spineis completed without removing a portion of the patient's lamina. Theinterlaminar window may be enlarged by use of surgical instruments, suchas distractors for example.

FIGS. 4A and 4B illustrate a first variation of the step of accessingthe spine location. As shown in FIG. 4A, the step of accessing spinelocation 100 of the patient may comprise advancing access device 40through access location 10 to the spine location. The access device maybe advanced into a midline portion of the back of the patient, lateralto spinous process SP, and toward the spine location. The access devicemay be inserted into a patient's back using an open techniquefacilitated by retractors 42. Alternatively, the access device, such asa probe or an epidural needle, may be inserted into a patient's backusing a mini-open or percutaneous technique. Relevant tissues, as shownin FIG. 4A, may include an intervertebral disc (D), ligamentum flavum(LF) and/or facet joint (F) tissue of a vertebra (V), which may impingeon non-target tissues, such as nerve root (NR) and/or cauda equina (CE),of the lumbar spine. The spine location is anterior to the posterioraspect of the ligamentum flavum and posterior to the dura mater of thespinal cord and cauda equina. As shown in FIG. 4B, a curved distalportion of access device 40 may be advanced to the spine location. Asshown, the access device may be advanced to a position between targetligamentum flavum (LF) and non-target nerve root (NR) tissues.

FIG. 5A illustrates a second variation of the step of accessing a spinelocation. In this variation, the step of advancing an access devicethrough the access location to the spine location may comprise advancingthe access device into a lateral side of the back of the patient,through an intervertebral foramen, and toward the spine location. Forexample, as shown in FIG. 5A, access device 40 may be placed from thelateral side of the patient and through an intervertebral foramen 12′.The access device may be inserted into a patient's back using amini-open or percutaneous technique. For example, the step of advancingan access device through the access location to the spine location maycomprise advancing a needle (such as an epidural needle) percutaneouslythrough the access location to the spine location. Alternatively, theaccess device, such as a probe, may be inserted into a patient's backusing an open technique facilitated by retractors. As shown in FIG. 5A,the access device may include steerable cannula 18 that may be advancedthrough access element 2 from the lateral towards the medial side of theintervertebral foramen toward spine location 100. Alternatively, aguidewire may be advanced through the cannula to access the spinelocation or the access device may have a curved end to access the spinelocation, as shown in FIG. 4A.

FIG. 7A illustrates a third variation of the step of accessing a spinelocation. As shown in FIG. 7A, an access device, such as epidural needle1060 (or cannula), may be passed through the patient's skin, and adistal tip of needle 1060 may be advanced through the ligamentum flavumLF of the spine into the spine location. In some variations, as shown inFIG. 7A, the spine location is the epidural space ES.

The step of inserting a flexible tissue modification device through theaccess location to the spine location positions a tissue modificationdevice such that it may be utilized to modify a target tissue. Theflexible tissue modification device may be passed through the channelcreated from the access location to the spine location. FIG. 4Gillustrates a first variation of the step of inserting a flexible tissuemodification device through the access location to the spine location.In this variation, the step of inserting a flexible tissue modificationdevice through the access location to the spine location comprisespulling flexible tissue modification device 52 through the accesslocation 10 and to the spine location 100 by pulling on guidewire 32,which is coupled to a distal portion of the tissue modification device.In this variation, once guidewire 32 is positioned in a desiredlocation, its proximal end with shaped member 50 may be coupled with acoupling member 62 on a distal end of a tissue modification device.Tissue modification device, in one embodiment, may include a proximalhandle 54, a rigid proximal shaft portion 56, a flexible distal shaftportion 58, tissue cutting blades 60, and coupling member 62. Thecoupling member may be either attached to or formed in distal shaftportion 58 of the tissue modification device. In some embodiments, suchas the one depicted in FIG. 4G, to attach the guidewire to a couplingmember, the guidewire may be laid into a channel on coupling member, andthe guidewire and/or distal portion may be rotated, relative to oneanother, to lock the shaped member into coupling member. Before, afteror during coupling of the guidewire and tissue modification device, theguidewire may also be coupled with distal guidewire handle 34, such asby advancing distal handle over the guidewire (solid-tipped arrow). Oncethe guidewire is coupled to the tissue modification device, the distalend of the guidewire and/or the distal handle may be pulled, therebypulling the tissue modification device along the path of the guidewire,through the access location and to the spine location.

In a second variation, the tissue modification device may be insertedthrough the access location to the spine location by pushing or pullingthe modification device over a guidewire to the spine location. In thisvariation, the guidewire may function as a track or rail that the tissuemodification device may be pushed or pulled over. In a third variation,the flexible tissue modification device may be inserted through theaccess location to the spine location without the use of a guidewire. Inthis variation, the tissue modification device may be pushed to thespine location by pushing on a proximal handle and/or proximal end ofthe tissue modification device.

The step of advancing a distal portion of the first flexible tissuemodification device from the spine location to a first exit location,further positions a tissue modification device such that it may beutilized to modify a target tissue. From the single access location, thetissue modification device may be advanced to one of several possibleexit locations. As shown in FIG. 3A, from access location 10, the tissuemodification device may be advanced to exit locations 12, 14, 16, 18, orany other suitable exit location. These exit locations may be through anintervertebral foramen. By advancing the tissue modification device fromthe spine location to exit location 12, the tissue modification devicemay be positioned to perform an ipsilateral disc level decompression(this may also be considered a lateral recess decompression). Byadvancing the tissue modification device from the spine location to exitlocation 14, the tissue modification device may be positioned to performan ipsilateral decompression along the nerve root (this may also beconsidered a foraminal decompression). By advancing the tissuemodification device from the spine location to exit location 16, thetissue modification device may be positioned to perform a contralateraldisc level decompression. By advancing the tissue modification devicefrom the spine location to exit location 18, the tissue modificationdevice may be positioned to perform a contralateral decompression alongthe nerve root. As shown in FIG. 3B, from access location 10, the tissuemodification device may be advanced to exit location 20. By advancingthe tissue modification device from the spine location to exit location20, the tissue modification device may be positioned to perform anipsilateral adjacent level lateral recess decompression. The tissuemodification device may alternatively be positioned to perform acontralateral adjacent level lateral recess decompression (not shown).As shown in FIG. 3C, from access location 10, the tissue modificationdevice may be advanced to exit location 22. By advancing the tissuemodification device from the spine location to exit location 22, thetissue modification device may be positioned to perform a central canaldecompression.

FIG. 8A illustrates a first variation of the step of advancing a distalportion of the first flexible tissue modification device. In thisvariation, the step of advancing a distal portion of the first flexibletissue modification device comprises advancing a guidewire from thespine location to the first or second exit location and pulling theflexible device around a target tissue using the guidewire. Guidewire 32may be coupled to a distal portion of the tissue modification device. Asshown in FIG. 8A, guidewire system 10 is shown with an embodiment of atissue modification device 64, which may include a proximal handle 66, arigid proximal shaft portion 68, and a distal flexible shaft portion 70.In this embodiment, guidewire 32 may be coupled with coupling member 74and used to pull distal shaft portion 70 of modification device 64 intoplace between target and non-target tissues.

FIGS. 9D-9E illustrate a second variation of the step of advancing adistal portion of the first flexible tissue modification device. In thisvariation, the step of advancing a distal portion of the first flexibletissue modification device comprises pulling the tissue modificationdevice into position by pulling on guidewire. Furthermore, the step ofadvancing the flexible device from the spine location to the exitlocation comprises positioning the flexible device at least partiallyaround a target tissue. In some embodiments, positioning the flexibledevice at least partially around the target tissue comprises positioningthe first or second flexible device anterior to a superior articularprocess and posterior to neuronal tissue, while in other embodiments,positioning the flexible device at least partially around the targettissue comprises positioning the flexible device within a portion of aligamentum flavum, as shown in FIG. 10.

Referring to FIG. 9D, distal handle 24 may then be pulled (hollow-tippedarrow) to pull device 10 into the patient and to thus position tissuemodifying members 16 in contact with target tissue TT. In someembodiments in which device 10 is used in the spine to treat spinalstenosis and/or neural or neurovascular impingement, device 10 may bepassed into the patient and to a position for modifying tissue withoutremoving any vertebral bone. More specifically, in some embodiments,device 10 may be advanced into the patient, through an intervertebralforamen, and out of the patient without removing bone. This is contraryto the majority of current surgical methods for treating spinalstenosis, which typically include removal of at least some vertebralbone, such as performing a laminotomy or laminectomy, and which oftenremove significant amounts of vertebral lamina, spinous process, facetand/or pedicle bony tissue, simply to access the surgical site. In oneembodiment, for example, device 10 may be advanced percutaneously intothe patient, used to remove ligamentum flavum only, and withdrawn fromthe patient, without removing any vertebral bone.

In a third variation, the tissue modification device may be advanced bypushing or pulling the modification device over a guidewire to the spinelocation. In this variation, the guidewire may function as a track orrail that the tissue modification device may be pushed or pulled over.In a fourth variation, the flexible tissue modification device may beadvanced without the use of a guidewire. In this variation, the tissuemodification device may be pushed to the desired location by pushing ona proximal handle and/or proximal end of the tissue modification device.

The step of passing through the first exit location and out of thepatient, functions to bring a portion of a device out of the patient tooffer a location for bimanual manipulation of the device. In someembodiments, the step of passing through the exit location and out ofthe patient comprises advancing through the intervertebral foramen andexiting the patient percutaneously with the guidewire, as shown in FIG.4D. While the guidewire may exit the skin, the step of passing through afirst or a second exit location may comprise leaving a proximal portionof the flexible tissue modification in the intervertebral foramen. Asshown, guidewire 32 may be advanced through guide member 46 and out ofthe patient's back, using sharpened tip 33 to facilitate passage throughthe patient's back tissue. Probe 40 may then be removed, as shown inFIG. 4E, leaving guidewire 32 in place between the target and non-targettissues, as shown in FIG. 4F. Also shown in FIG. 4F is a shaped member50 (in this embodiment, a ball) on the proximal end of guidewire 32. Asdescribed above, the shaped member is coupled to the flexiblemodification device such that the modification device can be pulled intoposition by the guidewire.

FIGS. 7C and 7D illustrate a second embodiment of the step of passingthrough the first exit location and out of the patient. As shown in FIG.7C, nerve probe 1062 may include a guidewire lumen through which aguidewire may be passed, once it is determined that device 1062 isplaced in a desired position between target and non-target tissue (e.g.,avoiding a nerve adjacent to the upper region). As shown in FIG. 7D,when epidural needle 1060 and probe 1062 are removed, guidewire 1064 maybe left in place between target tissue (such as ligamentum flavum LFand/or facet bone) and non-target tissue (such as cauda equina CE andnerve root NR). Any of a number of different minimally invasive orpercutaneous surgical devices may then be pulled into the spine behindguidewire 1064 or advanced over guidewire 1064, such as the embodimentshown in FIG. 23 and others described by the assignee of the presentapplication in other applications incorporated by reference herein.

The step of advancing the first or a second flexible tissue modificationdevice through the same access location to the spine location and to asecond exit location provides for decompressing a nerve root of thepatient at second locations along the nerve root from the same accesspoint as the first location decompressed. The same tissue modificationdevice can be removed from the first exit location and reinserted backthrough the same access location to a second exit location, oralternatively, a second tissue modification device can be advancedthrough the same access location to a second exit location. The tissuemodification devices may access several locations through any suitablepath. For example, in a first variation, the step of advancing theflexible device from the spine location to the first exit locationcomprises advancing the first flexible device from the spine location,anterior to a superior articular process and cephalad to a pedicle, andthrough a intervertebral foramen (following arrow 12 in FIG. 3A). Byfollowing this path, the tissue modification device may be positionedposterior to and adjacent to a first nerve root. The step of advancingthe flexible device from the spine location to the second exit locationcomprises advancing the flexible device from the spine location,anterior to a lamina and caudal to the pedicle, and through a secondintervertebral foramen (following arrow 14 in FIG. 3A). By followingthis path, the tissue modification device may be positioned posterior toand adjacent to a second nerve root. For example, in a second variation,the step of advancing the flexible device from the spine location to afirst exit location comprises advancing the first flexible device fromthe spine location, anterior to a superior articular process, andthrough a first intervertebral foramen (following arrow 12 in FIG. 3A),while the step of advancing the flexible device from the spine locationto the second exit location comprises advancing the flexible device fromthe spine location, anterior to a superior articular process, andthrough a second intervertebral foramen (following arrow 16 in FIG. 3A).

The methods as described may further comprise the steps of inserting aflexible tissue modification device through the same access location tothe spine location, and advancing the flexible tissue modificationdevice from the spine location to a third exit location. Alternatively,any suitable number of tissue modification devices may be insertedthrough the same access location, and advanced along any suitable pathwithin the spinal anatomy.

The methods as described may further comprise the steps of removing thefirst flexible tissue modification device from the patient and/orremoving the second flexible tissue modification device from thepatient. The tissue modification devices may be removed once themodification along the path through which they have been advanced iscompleted, alternatively, a first tissue modification device and asecond tissue modification device may be in a patient, through the sameaccess location, at the same time.

The methods as described may further comprise the steps of moving theflexible tissue modification device against the target tissue by pullingthe flexible tissue modification device from at least one of the distalor proximal end of the tissue modification device and/or modifying thetarget tissue with the flexible tissue modification device. The targettissue along the path of the tissue modification device may be modifiedby the modification device by moving the device along the target tissue.As described above, in some embodiments, the tissue modification devicemay be pulled through and moved along the target tissue by pulling thedevice from one end by a guidewire, or alternatively by pulling thedevice over the guidewire. In some embodiments, the step of moving theflexible tissue modification device against a target tissue by pullingthe flexible tissue modification device from at least one of the distalor proximal end of the device comprises applying tension to both theproximal end and the distal end of the flexible tissue modificationdevice to drive the flexible device against the target tissue.

FIG. 8A illustrates a first variation of the step of applying tension toboth the proximal end and the distal end of the flexible tissuemodification device. As shown, proximal handle 66 and distal handle 34may be pulled/tensioned (solid-tipped arrows) to urge abrasive members72 against the target tissue, and handles 66, 34 may further be used toreciprocate device 64 and guidewire 32 back and forth(hollow/double-tipped arrows) to modify the target tissue. Reciprocationand tensioning may be continued until a desired amount of tissue isremoved, at which point guidewire 32 may be released from distal handle34, and device 64 and guidewire 32 may be removed from the patient'sback. In various embodiments, tissue modification device 64 may includeany of a number of abrasive members 72, abrasive materials, or the like,which may be arrayed along distal shaft portion 70 for any desiredlength and in any desired configuration.

FIG. 9E illustrates a second variation of the step of applying tensionto both the proximal end and the distal end of the flexible tissuemodification device. As shown in FIG. 9E, once tissue modifying members16 are positioned as desired, relative to target tissue TT, proximalhandle 20 and guidewire handle 24 may be pulled (hollow-tipped arrows)to urge tissue modifying members 16 against target tissue TT(solid-tipped, single-headed arrows). While maintainingpulling/tensioning force, handles 20, 24 may be used to reciprocatedevice 10 back and forth (solid-tipped, double-headed arrows) to removetarget tissue TT. When a desired amount of tissue is removed, device 10may be removed from the patient, such as by detaching guidewire handle24 from guidewire 22 and pulling proximal handle 20 to withdraw device10 and guidewire 22 out of the patient. Device 10 or an additionaldevice may be reinserted into the patient and used in a second locationto remove additional tissue. For example, in a spinal stenosis treatmentprocedure, device 10 may be used to remove tissue from (and thusdecompress) a first intervertebral foramen and then may be removed andreinserted to remove tissue from a second foramen. This process may berepeated to remove tissue from any number of foramina. In oneembodiment, device 10 may include a guidewire lumen, so that a guidewiremay be placed into a second foramen while device 10 is in the epiduralspace of the patient. Device 10 may then be removed along with the firstguidewire 22, attached to the second guidewire, and reinserted into thesecond foramen to remove tissue. In some embodiments, tissue may beremoved from device 10 before reinserting device 10 into the patient toremove more tissue.

The methods as described may further comprise the step of detectingneuronal tissue near the flexible tissue modification device. This stepmay be performed to ensure that the tissue modification device ispositioned such that the neuronal tissue; such as the nerve root, or thedura mater of the spinal cord and cauda equina; will not be modified bythe tissue modification device. The tissue modification device mayinclude at least one electrode to locate the position of the detectingneuronal tissue or alternatively, a separate device may be inserted andadvanced into location.

In some embodiments, as shown in FIG. 5A, the method of accessing targettissue adjacent to a spinal nerve of a patient may alternatively includethe steps of accessing a spine location 100 of the patient by enteringthe patient through the skin at a first access location; inserting aflexible tissue modification device 102 through the first accesslocation 12′ to the spine location 100; advancing a distal portion ofthe first flexible tissue modification device from the spine location toan exit location 10′, as shown in FIG. 5B; passing out of the patientthrough the first exit location; advancing the first or a secondflexible tissue modification device through the same access location tothe spine location and to a second exit location; and passing throughthe second exit location and out of the patient. The spine location maybe anterior to the posterior aspect of the ligamentum flavum LF andposterior to the dura mater of the spinal cord and cauda equina CE. Insome embodiments, as shown in FIG. 4A, the spine location may be theepidural space. The methods are designed for accessing target tissue,and more specifically, for accessing and decompressing a spinalstenosis. The methods however, may be alternatively used for any othersuitable disease, in any suitable environment and for any suitablereason.

Tissue Modification Devices

As described, the tissue modification devices typically include aflexible elongate body that extends proximally to distally(proximal/distal), and is configured to be inserted into a patient sothat it extends around the target tissue, so that it can be bimanuallypulled against the target tissue by applying tension to either end ofthe device. Thus, the device may be extended into and through and arounda spinal foramen. The device is flexible in at least one plane. Forexample, in variations in which the device has an elongated ribbon shapethat is long and flat with a width greater than the thickness, thedevice includes a first major surface (e.g., a front) and a second majorsurface (a back), and has edges (minor surfaces) connecting the firstand second major surfaces. The first major surface may be referred to asthe anterior or front surface and the second major surface may bereferred to as the posterior or back surface. The devices describedherein may be flexible along the anterior and posterior surfaces, andthe anterior or front surface may include one or more cutting edgesconfigured to cut tissue as the anterior surface of the device is urgedagainst a tissue. The posterior surface may be configured to shield orprotect non-target tissue.

For example, as shown in FIG. 11, in some embodiments, the tissuemodification devices typically include one or more of the followingfeatures: all or a portion of the device maybe formed of flexiblyconnected rungs or links; the devices may include a tissue captureregion having a fixed minimum volume; and the device may be configuredso that the major/minor surfaces may have non-linear shapes along theirlength, or may be stitched between linear and non-linear shapes. Atissue modification device may include one or more of these features inany combination. Each of these features is described and illustrated ingreater detail below.

As shown in FIG. 8A, an embodiment of a tissue modification device 64may include a proximal handle 66, a rigid proximal shaft portion 68, anda distal flexible shaft portion 70. Multiple abrasive members 72 and aguidewire coupling member 74 may be coupled with one side of flexibleshaft portion 70. Proximal handle 66 and distal handle 34 may then bepulled/tensioned (solid-tipped arrows) to urge abrasive members 72against the target tissue, and handles 66, 34 may further be used toreciprocate device 64 and guidewire 32 back and forth(hollow/double-tipped arrows) to modify the target tissue. Reciprocationand tensioning may be continued until a desired amount of tissue isremoved, at which point guidewire 32 may be released from distal handle34, and device 64 and guidewire 32 may be removed from the patient'sback. In various embodiments, tissue modification device 64 may includeany of a number of abrasive members 72, abrasive materials, or the like,which may be arrayed along distal shaft portion 70 for any desiredlength and in any desired configuration. Further examples of abrasivemembers 70, materials, surfaces and the like are described in U.S.patent application Ser. No. 11/429,377, which was previouslyincorporated by reference. In various alternative embodiments, shaftportions 68, 70 may both be rigid or may both be flexible and may havedifferent cross-sectional shapes or the same shape.

As shown in FIG. 8B, an alternative embodiment of the tissuemodification device is an ultrasound tissue modification device 76 thatmay also be advanced into position in a patient's back using guidewiresystem 10. In one embodiment, for example, ultrasound device 76 mayinclude a proximal handle 78, a hollow shaft 80 having a distal window81, multiple ultrasound wires 82 extending through shaft 80 and intowindow 81, a guidewire connector 84 coupled with a tapered distal end ofshaft 80, an ultrasound generator 88, and a wire 86 coupling handle 78with generator 88. Handle 78 may include, for example, an ultrasoundtransducer, horn and/or other ultrasound transmission components. Shaft80 may be completely rigid, completely flexible, or part rigid/partflexible, according to various embodiments. Ultrasound energy providedby generator 88 may be converted in handle 78 to reciprocating motion ofwires 82, and reciprocating wires 82 may be used to cut, chisel orotherwise modify soft and/or hard tissues. Further description of suchan embodiment is provided in U.S. patent application Ser. No.11/461,740, which was previously incorporated by reference. Guidewireconnector 84 may comprise one of a number of different connectors,various embodiments of which are described in further detail below.

In another embodiment, and with reference now to FIG. 8C, guidewiresystem 10 may be used to pull/advance a tissue access device 90 intoplace between target and non-target tissues. Tissue access device 90,for example, may include a proximal handle 92, a hollow shaft 94 havinga distal curved portion with a distal window 96, and a guidewireconnector 98 coupled with a tapered distal end of shaft 94. As withpreviously described embodiments, shaft 94 may be flexible along itsentire length, rigid along its entire length, or rigid in part andflexible in part, and may be made of any suitable material orcombination of materials. In some embodiments, shaft 94 may also besteerable, such as with one or more pull wires or other steeringmechanisms, for example to steer or curve a distal portion of shaft 94.

Once access device 90 is in a desired position, with window 96 facingtarget tissue (such as ligamentum flavum and/or facet joint bone in thespine) and an atraumatic surface of shaft 94 facing non-target tissue,any of a number of compatible tissue modification devices 100, 101, 104or other devices may be advanced through access device 90 to perform atissue modification procedure or other functions. Such devices mayswappable in and out of access device 90 and may be in the form ofcartridges, so that various cartridges may be inserted and removed asdesired, over the course of a procedure. Examples of several tissuemodification devices are shown in FIG. 8A, including a rongeur device100, an ultrasound device 101 (including wire 102 and ultrasoundgenerator 103), and an abrasive, reciprocating device 104. Furtherexamples of tissue modification and other devices are described belowwith reference to FIGS. 8B-8M.

In one embodiment, for example, at least a distal portion of each tissuemodification device 100, 101, 104 may be flexible, and a proximalportion of each modification device 100, 101, 104 may have a lockingfeature for locking into proximal handle 92 of access device 90. Thus, agiven modification device, such as abrasive device 104, may be advancedinto handle 92 and shaft 94, so that abrasive members 105 of device 104are exposed through window 96 and locking feature 99 of device couplesand locks within handle 92. A user may then grasp handles 34 and 92,pull up to urge abrasive members 105 against target tissue, andreciprocate access device 90 and guidewire system 10 back and forth toremove target tissue. The user may then choose to remove abrasive device104 and insert one of the other devices 100, 101 to further modifytarget tissues.

In various embodiments, any of a number of tissue modification devicesand/or other devices may be provided (for example as cartridges) forused with access device 90. In some embodiments, one or more of suchdevices may be provided with access device 90 and guidewire device 10 asa system or kit. Any given tissue modification device may act on tissuein a number of different ways, such as by cutting, ablating, dissecting,repairing, reducing blood flow in, shrinking, shaving, burring, biting,remodeling, biopsying, debriding, lysing, debulking, sanding, filing,planing, heating, cooling, vaporizing, delivering a drug to, and/orretracting target tissue. Non-tissue-modifying devices or cartridges mayadditionally or alternatively be provided, such as but not limited todevices for: capturing, storing and/or removing tissue; delivering amaterial such as bone wax or a pharmacologic agent such as thrombin,NSAID, local anesthetic or opioid; delivering an implant; placing arivet, staple or similar device for retracting tissue; delivering atissue dressing; cooling or freezing tissue for analgesia or to changethe tissue's modulus of elasticity to facilitate tissue modification;visualizing tissue; and/or diagnosing, such as by using ultrasound, MRI,reflectance spectroscopy or the like. In given method, system or kit,any combination of tissue modification and/or non-tissue-modifyingdevices may be used with access device 90. In some embodiments, thetissue modification device may be a radio-frequency device, which insome embodiments heats, ablates, and/or shrinks the target tissue.

Although preferred illustrative embodiments are described herein, itwill be apparent to those skilled in the art that various changes andmodifications may be made thereto without departing from the invention.It is intended in the appended claims to cover all such changes andmodifications that fall within the true spirit and scope of theinvention.

1. A method of accessing target tissue of a patient, comprising:accessing, through an access location, a spine location of the patient;inserting a flexible device through the access location to the spinelocation; advancing a distal portion of the flexible device from thespine location to a first exit location; passing the flexible devicethrough the first exit location and out of the patient; pulling in atissue modification element through the access location to the spinelocation and positioning the tissue modification element at leastpartially around a target tissue; modifying the target tissue with thetissue modification element; advancing a distal portion of the flexibledevice from the spine location to a second exit location; passingthrough the second exit location and out of the patient; pulling in thefirst or a second tissue modification element through the accesslocation to the spine location and positioning the tissue modificationelement at least partially around a second target tissue; and modifyingthe second target tissue with the tissue modification element.
 2. Themethod of claim 1, wherein the step of modifying the target tissue withthe first or second tissue modification element comprises decompressinga nerve root of the patient at multiple locations along the nerve root.3. The method of claim 2, wherein decompressing the nerve root of thepatient at multiple locations along the nerve root comprisesdecompressing the nerve root at least two of a central canal, a lateralrecess, and through an intervertebral foramen.
 4. The method of claim 1,wherein the step of advancing the flexible device to a first or secondexit location comprises advancing the flexible device to a first orsecond intervertebral foramen.
 5. The method of claim 1, wherein thestep of accessing a spine location of the patient through an accesslocation comprises advancing a probe through the access location to thespine location.
 6. The method of claim 5, wherein the step of advancingthe probe through the access location to the spine location comprisesadvancing the flexible device through the probe to the spine location.7. The method of claim 6, wherein the flexible device is a guidewire. 8.The method of claim 7, wherein the step of passing through the first orsecond exit location and out of the patient comprises advancing theguidewire through the first or second exit location and exiting thepatient with the guidewire.
 9. The method of claim 1, wherein theflexible device is a guidewire.
 10. The method of claim 9, wherein thestep of pulling in the first or a second tissue modification elementcomprises pulling the tissue modification element at least partiallyaround the target tissue using the guidewire.
 11. The method of claim 9,wherein the step of pulling in the first or a second tissue modificationelement comprises pulling in the tissue modification element that isintegrally connected to a proximal end of the guidewire.
 12. The methodof claim 9, wherein the step of pulling in the first or a second tissuemodification element comprises pulling in the tissue modificationelement having a guidewire coupler at the distal end that is coupled toa proximal end of the guidewire.
 13. The method of claim 12, wherein thestep of passing through the first or second exit location and out of thepatient comprises exiting the patient percutaneously with the guidewire.14. The method of claim 1, wherein the step of modifying the first orsecond target tissue with the first or second tissue modificationelement comprises modifying the first or second target tissue with aflexible abrasion device.
 15. The method of claim 1, further comprisingthe step of detecting neural tissue near the first or second tissuemodification element.
 16. The method of claim 15, wherein the step ofdetecting neural tissue near the first or second tissue modificationdevice comprises detecting neural tissue with the first or second tissuemodification device.
 17. The method of claim 15, further comprisingpulling in a neural localization element through the access location tothe spine location and positioning the neural localization element atleast partially around a target tissue and detecting neural tissue withthe neural localization element.
 18. The method of claim 17, wherein thestep of pulling in a neural localization element comprises pulling theneural localization element at least partially around a target tissueusing the guidewire.
 19. The method of claim 1, wherein the step ofpassing through the first exit location and out of the patient comprisespassing through the skin and out of the patient.
 20. A method ofaccessing target tissue of a patient, the method comprising: accessing aspine location of the patient by entering the patient through an accesslocation, wherein the spine location is anterior to the posterior aspectof the ligamentum flavum and posterior to the dura mater of the spinalcord and cauda equina, and the access location is lateral to the spinousprocess; inserting a flexible device through the access location to thespine location; advancing a distal portion of the flexible device fromthe spine location, through a first intervertebral foramen, and out ofthe patient; pulling in a tissue modification element through the accesslocation to the spine location and positioning the tissue modificationelement at least partially around a target tissue; modifying the targettissue with the tissue modification element; advancing a distal portionof the flexible device from the spine location, through a secondintervertebral foramen, and out of the patient; pulling in the first ora second tissue modification element through the access location to thespine location and positioning the tissue modification element at leastpartially around a second target tissue; and modifying the second targettissue with the tissue modification element.
 21. The method of claim 20,wherein the step of inserting the flexible device through the accesslocation comprises inserting the flexible device through an interlaminarwindow of the patient and to the spine location.
 22. The method of claim20, wherein the step of advancing the flexible device from the spinelocation comprises advancing the flexible device laterally from thespine location through the first intervertebral foramen.
 23. The methodof claim 20, wherein the step of advancing the flexible device from thespine location through a first intervertebral foramen comprisespositioning the flexible device posterior to and adjacent to a firstnerve root, wherein the first nerve root exits through the firstintervertebral foramen.
 24. The method of claim 20, wherein the step ofadvancing the flexible device from the spine location through a secondintervertebral foramen comprises positioning the flexible deviceposterior to and adjacent to a second nerve root, wherein the secondnerve root exits through the second intervertebral foramen.
 25. Themethod of claim 20, wherein the step of advancing a distal portion ofthe flexible device out of the patient comprises advancing a distalportion of the flexible device through the skin and out of the patient.